Relay



Sept. 22, 1931.

"RELAY Filed July 27, 1926 4 Sheets-Sheet 1 Ill Fl B. 1 1NVEN TOR.

o. s. FIELD 1,824,129 7 Sept. 22, 1931.

o. s. FIELD RELAY Filed July 27, 1926 4 Sheets-Sheet 2 INVEN'J uR.

0. S. FIELD Sept. 22, 1931.

RELAY Filed July 27, 1926 4 Sheets-Sheet 3 Omv uw mm kw m wk E

g m i INVENTOR.

Sept. 22, 1931 o. s. FIELD RELAY Filed July. 27, 1926 4 Shets-Sheet 4 no I m m mmmmmm FIBB INVEN TOR.

Patented Sept. 22, 1931 UNITED STATES PATENT OFFICE OSCAR S. FIELD, OF ALBANY, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK RELAY Application filed July 27,

This invention relates to improvements in direct current relays, more particularly that type of relay used in connection with railroad signalling. 5 One of the objects of the invention is to provide a relay that has a very high relative efiiciency. A further object is to provide a relay which is dependable in its operation, and which will not materially change its operating characteristics .over a fixed working period. A further object is to provide means whereby the relay can be readily assembled and adjusted and, further, whereby the contact tension airgap and other vital operating functions may be readily adjusted, to maintain a uniform operating characteristic in all relays manufactured of the same type.

With these objects in view and further objects as may appear from the following specification and appended claims, I will now proceed to describe one embodiment of my invention, together with its means of operation.

Figure 1 is a cross section through the relay from front to rear. Figure 2 is a plan view of the relay in the inverted position and with its cover glass removed. Figures 3, 4 and 5 are upper and lower plan views and a cross section of the finger structure employed in the I relay. Figures 6, 7 and 8 are side elevation, transverse section, and inverted plan view respectively, of the front contact carrying member.

Broadly speaking, the delay comprises an assembly of 3 unitary constructions, the first consisting of the magnetic system with its mounting plate, armature andcontact fingers, the second comprising the insulating top of the relay equipped with contacts adapted to co-act with the before mentioned contact fingers, and the third unit comprises the cover glass adapted to encase the moving parts and keep them free from dust and moisture.

The first structure comprises a metallic base plate 1 in which are suitably mounted Norway iron cores 2 and 3 respectively. These cores are provided with enlarged pole shoes 4 and 5 which serve the purpose of increasing the area of the operating airgap 6 in addition to providing means for mounting the cores 2 and 3 in the base plate 1 by means of screws 7 as 1926. Serial N0. 126,914.

indicated in Figure 2, which are adapted to pass through the base platen into holes tapped into the pole shoes. The cores 2 and 3 are provided with operating windings 8 and, further, provided with cross connecting yokes 9 and 10, rigidly clamped to flattened surfaces 11 and 12 formed on the core extremities by means of suitable bolts and nuts 13. It is, of course, understood that the connecting yokes 9 and 10 are made of suitable flux conducting material such as Norway iron.

In order to provide terminals for the coils 8, I propose to furnish asupporting Pilate 14 which is clamped by the bolts and nuts 13 to the core assembly and is adapted to carry an insulating block 15, supported thereon by means of screws and nuts 16, the insulating block 15 in its turn supporting binding posts 17 adapted to be connected by means of leads 18 to the coils 8.

On the under side of base plate 1 there is formed downward extensions 19 and 20 respectively. These extensions are provided with supporting studs 21, the purpose of which is toadj ustably support bearing'plate 22, this plate being arranged to have perforations in extended cars 23 and 24 adapted to slide over the studs 21. Adjusting nuts .25 are provided on the studs 21 whereby the bearing plate 22 may be adjusted up and down in a vertical plane, thereby forming a means of adjustment for the airgap 6. In operative relation to pole shoes 4 and .5 and adapted to co-act therewith an armature 26 of suitable material such as Norway iron is provided. This armature has riveted thereto at 27 and 28 respectively trunnion carrying arms 29 and 30. The arm 29 is provided with a trunnion member 31, adapted to 'beadjusted horizontally therein and to co-act with 'bexring member 32 on bearing plate 22. This trunnion member 31, after it has been set horizontally in the proper position, is drilled and permanently riveted in place by means of rivet 33. The arm 30 is provided with a n5 trunnion member 34, having an enlarged head 35 which is adapted to engage the inner surfaces of the arm 30. This trunnion member is provided with'a locking groove 36 through which a locking screw 37 18 passed, said screw being adapted to screw into the trunnion arm 30. V The trunnion arm 30 1s further provided 1 with a slot 38'whereby upon the tightening of screw 37, the trunnion member 34 is rigidly clamped in place. The trunnion member 34 1 by the armature may be readily adjustedin a vertical plane in relation to its pole shoes 4 and 5 respectively.

- The armature 26 1s provided with stop pins 40 which are adapted to maintain a minimum airgap betweenthe pole shoes and armature, in order'to prevent what is known as freezing, due to retention ofresidual magnetism in the iron'structure.

()nthe underside of armature 26 insulating studs 41 are provided, these-studs being made of insulating'material equipped with metallic threaded inserts 42 and 43 in a manner well known in the art. These studs 1 are adapted to carry the contact finger assemblies. 44.

In connection with the finger assembly 44, it is the purpose to provide a contact finger which 7 may be adjusted vertically relative to the armature in order to compensate for Varying airgap adjustments and irregularities in manufacture andalso to provide a contact element in which we may readily adjust the contact pressure andalso readily remove the contact elements. In order to accomplish these purposes, I have provided a finger which has a main channel section 45, the rear end of which is reduced to a simple flat section as shown .at 46 in Figure 4. The channelis provided with an adjusting nut 47 which passes through an aperture 48 in the channel structure 45 and through a washer 49-being spun over onthe upper side as shown at 50, whereby the nut is. rigidly connected to the channelmember 45. so far as vertical play is concerned but. is free to rotate therein. The flat section 46 of the channel member is and it is rigidly clamped in place by means ofa clamping nut 52. The adjusting nut 47 is adapted'to eng e the front stud 42, where- "a: by upon rotation of the nut the channel member-"45 will be hinged aboutedge 53 and will be'caused to move upor down in accordance with the direction of rotationof the adjusting nut 47. A locking plate 54 is provided and is adapted to pass underthe nuts 52 and 47 whereby, after the finger assembly has been ,properly adjusted, the edges of the locking plate may be turned up about the hexagonal sides of the nuts as indicated at 55, there by locking them against rotation. It will be seen that this combination comprises a means for adjustably mounting the main elementiof thefinger' assembly on the armature whereby it may be adjusted to its proper position and then rigidly locked in place. The frontendiot the channel section 45 is provided with a slot 56 and is further provided with a rear contact spring 57 equipped with a silver contact point 58 and riveted to the channel member 45 as shown at 59. The contact spring is provided with a narrow section 60. adapted to pass through the slot 56 and is bentover so as to engage with the channel member '45 asindicated at 61, thereby retaining a definite amount of trapped pressure in the spring 57 In order to adjust the trappedp'ressure all that is" necessary is to spring the front end62 of spring 57' forward so that the spring becomes disengaged from the channel member 45, thereby allowing any, desirable set to be put in the spring 57 after which it is again allowed to snapback into place. 7

V vVhenthe contact 58 co-acts with its complementary contact member the spring 57 is compressed until the shoulders 63 engages with the sidesof the slot 56 in channel member 45, thereby limiting the amount of com pression on spring 57. g

Behind the rivets 59 in channel member 45, a combination clamping screw and pivot point 64 is provided and is adapted to pass through the channel member 45 and beheld in place by means of the nut 65, said nut being held from.

rotation by means of indentations 66 formed in the channel member 45. Member 64 performs two functions. The first function is to provide a pivot over which'the contact carrying element 67 may rock, and the second is to provide means for clamping the eyelet 68 of pigtail69 rigidly to the channel member 45, whereby good electrical. contact is maintained.

The upper contact carrying member-'67 is provided with an indentation 7 0 arranged to co-act with the pivot 64; It is provided at its frontend with a downwardly extending lip 71 adapted to pass thru'slot 56 of channel member 45. The lip 71 is larger at its lower end 72 so that it will engage the sides of 74 in the member 67 and is equipped with an adjusting nut '75 and a locking nut 7 6, the operat on of whlch will be described hereafter The channel member isprovided with a recess 77 on the under side thereof for the purpose of centralizing the spring 78 which maintains the spring stud 73 under tension. It will be seen that if the spring stud 73 is rotated it will either tighten up on the pressure of spring 7 8 or reduce the same, accord ing to the direction of rotation, thereby varyingthe tension through nut on the rear end of front contact carrying member 67. In this way it is obvious that the tension necessary'to depress the front end of member 67 may be varied. In order to adequately lock the stud 73 from rotation when adjustments are not being made, upwardly extending cars 79 are provided on member 67. The stud 73 is provided with a nut 76 which ispinned to the stud by means of a pin 80, whereby the nut .76 must rotate in unison with the stud 73. In order to rotate the stud 73 therefore, it is necessary to compress the spring 78 so that the locking nut 76 may extend above the ears 79. The stud is then free to be rotated in either direction but upon release of the pressure the nut will drop down between the cars 79, thereby rigidly locking the stud from further rotation.

I have shown on the front end of the contact carrying member 67 a contact element which is known in the art as a gauze contact. This comprises a spring supporting frame 81 riveted to member 67 at 82 as shown. Mounted in this frame is a silver gauze contact 83, said contact being equipped with end supporting pieces 84 and 85 adapted to engage with hook members 87 and 86 respectively on the spring supporting member 81. From this construction it is seen that this member may be readily removed by squeezing the spring carrying member 81 together,

thereby allowing the gauze element to be lifted out. This construction is not new and is well known in the prior art.

In the present embodiment, the gauze element is equipped with an extension 88 adapted to carry a. pi tail 69 which is connected to member 45 as previously described. By this construction I have provided means whereby the spring element 81 is not called upon to carry current from the gauze contact 83 to the finger structure proper. The practice of using this member as a current carrying element has been found in practice to be detrimental to the proper functioning of the contact owing to variable resistance conditions in the connection between the gauze and the spring element. In some cases this has caused failures due to excessive heat generated at v this point which draws the temper of the spring supportingmember.

I have now fully described the various elements incorporated in section one of the assembly.

Section two consists of a top 89 made of suitable insulated material such as bakelite.

cesses adapted to carry contact carrying stir rups 94 with their co-acting binding posts 95 and back contact elements 96, said contact elements being carried in such a position as to be in operative relation with the back contact 58 of the contact finger 44. When the relay is de-energized the contacts 58 rest on the co-actin-g contacts 96 and the contacts act as back stops to limit the dropping-away movement of the armature 26. It will be seen that by bending the stirrups 94 up or down at point 97, the dropping-away movement of the armature may be readily adj usted.

To co-act with the gauze contact elements 83 front contacts 98, more particularly illustrated in Figures 6 to 8 inclusive, are provided. These contacts are usually made of carbon or some other suitable nonfusing material. It is desirable in connection with these contacts to mount them in the top 89 if in such a manner that they cannot be disturbed from the outside of the relay. In order to accomplish this, I have provided a special binding post 99 equipped with a square head 100 and adapted to be screwed T through a nut 101 which is set in a hexagonal recess 102 in the top 89 whereby the nut 101 cannot turn. A clamping element 103 is provided which is adapted to pass over the shank of contact stud 99 and. rest on the upper r side of the square head 100 as shown at 104. This member is provided with an extension 105 which projects beyond the edge of the square head 100. A screw 106 is passed through the member 103 and threaded into the square head 100 and adapted to project through as shown at 107. This screw rigidly locks member 103 to the head 100 and provides means for rcmovably clamping the carbon block 98 as will hereafter be described. The member 103 is further provided, with an extending ear 108 which is adapted to engage in a recess 109 formed in the top 89. It will be seen that after the contact combination has been screwed in place and the car 108 depresesd into the recess 109 as clearly shown in Figures 7 and 8, that the post will be rigidly locked from rotation and it will be impossible to remove it from the top 89 unless the car 108 is raised from the slot 109. 103 has a downwardly extending part 110 which is adapted'to engage the contact block 98 which is suitably beveled in order to facilitate the clamping action.

A co-acting plate 111 is provided which has a clamping part 112 complementary to opening at 113 through which the end 107 of screw 106 )asses and is ada Jted to en a e the ED D end 105 of member 103.- It will be seen that when this member is clamped in place by means of a nut 11 1 that the element 112 will rigidly clamp the carbon'block 98 between members 112 and 110. The carbon 98 is pro-v vided with a hole .115 therethrough and an ear 116 is formed on member 112 and adapted to pass into the hole 115. The purpose of this is to form a safety feature to prevent the carbon block 98 from dropping should. it become loose.

The relation of the co-acting contacts and the contacs 011 the contact finger are clearly shown in Figure 1 and they are soadjusted that when the relay is tie-energized the back contacts will close and the front contacts open and when the relay is energized the front contacts will close and the back contacts open in-such a manner as to give a definite amount of compression to the springs 78.

in order to obtain electrical connectionto in which a suitable gasket, preferably of felt 122 is provided. This gasket is for the purpose of coasting with the third element of the structure, that is the enclosing case 123. This case is preferably moulded in transparent glass so that the operation of the relay may be readily inspected at any time. The glass is provided with suitable legs 12 1 which have recesses 125 in which supporting springs 126 may be cemented when the relay is used as a shelf type relay.

3 manner The spring 126 is for the purpose of absorbing undue shock and vibration.

which passes a clamping stud 129 suitably supported from top 89. The glass is held in place'by means of the clamping nut 130 being suitably protected inst crushing effectsby a rubber washer 131. Should it be desirable to mount the relay upon the wall, wall hangers 132 may be provided being made of a resilient material and rigidly attached to mounting plate 1. In this the relay-may be rigidly mounted to the wall and the greatest element of weight will be directly ca ried through the contact supporting plate 1 rather than through the insulating top 89. thereby relieving this top of any undue strains in service. 7

While 1 have described and illustrated one form of my invention, it is'to be understood that I may depart from many of the details of construction without departing'from the spirit of the invention.

-What I'claim is I 1. Incombination in a relay a supporting top, an electromagnetand co-acting armature carried by said top, contact fingers on said armature front and back contacts carried by said top in operative relation to said contact fingers, adjusting means whereby said contact fingers may be individually adjusted on said armature and locking means for said'adjusting means. i r

2. in combination in a relay, a supporting top, an el-ectromagnet carried by said top, a co-acting armature, removably supported by said top, contact fingers on said armature, frontand back contacts carried by said top in operative relationto said contact fingers, and means whereby the end play of said armature may be adjusted during manufacture and then permanently set whereby the armature may befremoved and replaced without disturbing the end play and whereby need for I-Ltreme accuracy in manufacture is obviated.

top, an electromagnet and co-coacting armature carriedjby said top, a contact finger on said armature comprising a main member;

having a back contact, and provided with a pivot 3011113 intermediate its len 'th and a l l c:

contacts carried by said top in operative relation to said fingers whereby upon energization of the relay the front contacts co-act to cause the secondary-front contact carrying member to rock about. the pivot point and compress the spring.

41. in combination in a relay, a supporting top an electromagnet and coacting armature carried said top a contact finger on said armature a front contact on said finger having aslot formed in the end thereof'and a coacting front contact carried by said top, a back contact spring rigidly attached to said finger at one end and free to pass through the slotin the finger at the other end and having said end bent over whereby a definite spring pressure is trapped, a contact on said the-pressure onrthe back contacts when the relay is deenergized.

5. in combination in a relayya supporting top. an electromagnet and coacting armature carried by said top, a contact finger on said armature comprising a mam member, a pivot point on the main member and a secondary contact carrying member loosely resting thereon to be oscillatably mounted thereon, a

. energization of the relay.

6. In combination in a relay, a supporting top, an electromagnet and coacting armature carried by said top, a contact finger on said armature, a gauze contact, spring supporting means on said finger adapted to support said gauze contact, coacting contacts carried by said top, an extension on said gauze contact adapted to carry a current conducting pigtail, and a pigtail between said extension and said finger whereby current passing through the contacts will be bypassed to l the finger thereby avoiding heating of the spring supporting means.

7. In combination in a relay, a supporting top, an electromagnet and coacting armature carried by said top, a contact finger insulatively mounted on said armature having both front and back contacts, a coacting back contact supported by said top, a coacting front contact and supporting means adapted to be screwed into said top and provided with a lateral extending ear adapted to engage with a recess formed in said top whereby said contact supporting means is locked against rotation.

8. In combination in a relay, a supporting top, an electromagnet and coacting armature carried by said top, fixed contacts carried by said top, a coacting contact finger of rigid cross section having a flexible rear extension, means for rigidly attaching said extension to said armature, and threaded adjusting means associated with the rigid section whereby the finger may be caused to hinge about the flexible rear extension whereby the finger may be adjusted relative to its fixed contacts.

9. In combination in a relay, a supporting top, an electromagnet and coacting armature carried by said top, fixed contacts carried by said top, a coacting contact finger of channel section having a flattened rear extension,

, means for rigidly attaching said extension to said armature. and threaded adjusting means associated with the rigid section whereby the finger may be caused to hinge'about the flexible rear extension whereby the finger may be adjusted relative to its fixed contacts.

10. In combination in a relay, a supporting top, an electromagnet and coacting armature carried by said top, fixed contacts carried by said; top, a coacting contact finger of rigid cross section having a flexible rear extension,

means .for rigidly attaching said extension to said armature, and an adjusting nut rotatably mounted in the rigid section in spaced relation from the flexible extension and adapted to coact with a supporting stud on said armature whereby the finger may be caused to hinge about the flexible rear extension whereby the finger may be adjusted relative to its fixed cont-acts.

11. In combination in a relay, a supporting top, an electromagnet and coacting armature carried by said top, fixed contacts carried by said top, a coacting contact finger of channel section having a flattened rear extension, means for rigidly attaching said extension to said armature, and an adjusting nut rotatably mounted in the channel section in advance of the flattened section and adapted to coact with a supporting stud on said armature whereby the finger may be caused to hinge about the flexible rear extension whereby the finger may be adjusted relative to its fixed contacts.

12. In combination in a relay, a supporting top, an electromagnet and coacting armature carried by said top, fixed contacts carried by said top, a coacting contact finger of rigid cross section having a flexible rear extension, means for rigidly attaching said extension to said armature, and an adjusting nut rotatably mounted in the rigid section in spaced relation from the flexible extension and adapted to coact with a supporting stud on said in mature whereby the finger may be caused to hinge about the flexible rear extension whereby the finger may be adjusted relative to its fixed contacts and means for locking said adjusting nut.

13. In combination in a relay, a supporting top, an electromagnet carried by said top, a coacting armature removably supported by said top, a contact finger insulatively mounted on said armature, front and back contacts carried by said top in operative relation to said contact finger and two trunnions associated with said armature one of which is adapted to have an initial horizontal adjustment and then be permanently fixed and the other having no horizontal adjustment but being removably mounted whereby said armature may be removed from the relay without disturbing the end play adjustment.

14. In combination in a relay, a supporting top, an electromagnet carried by said top, a coacting armature rcmovably supported by said top, a contact finger mounted on said armature, a fixed contact carried by said top in operative relation to said contact finger and trunnions for supporting said armature, one of which is headless and adapted to be adjusted horizontally during manufacture and the other being provided with a head and removably attached whereby the armature may be removed from the relay without disturbing the horizontal adjustment.

15. In combination in a relay, a supporting top, an electromagnet carried by said top, a coacting armature removably supported by said top, fixed contacts carried by said top, a coacting contact finger of rigid cross section having a flexible rear extension, means for insulatively attaching said extension to finger may be caused to hinge about the flexi ble rear extension and trunnions associated with said armature one of which is adapted to have an initial horizontal ad ustment and thenbe permanently fixed and the other having no horizontal adjustment but being removably mounted whereby the contact finger may be adjusted as to end play and vertical i vried by said top, a coacting armature,

. top,

position in relation to its coacting contact and the armature may be readily reinovable without disturbing this adjustment;

16. In combination in a relay, a supporting an electromagnet carried by said top, downwardly depending supporting studs carmeans comprisingja bearing plate adapted to slide vertically on'said supporting studs for supporting said armature whereby it may be adjusted in relation to the permanent magnet, fixed contacts carried by said top, a coacting contact finger of rigid cross section having a flexible rear extension, means for insulative 1y attaching said extension to said armature, threaded adjusting means associatedwith the rigid section whereby the finger may be caused to hinge aboutthe flexible rear extension and trunnions assoc ated with said armature one of which is adapted to have an initial hori-' zontal adjustment and then be permanently fixed and the other having no horizontal adjustment but being removably mounted whereby the contact finger maybe adjusted as to end play and vertical position in relation to its coacting contact and the armature may be readily removable without disturbing e) this adjustment.

1 17. 'In combination in a relay, a suppoiting top, an electromagnetcarried by said top,

- supporting studs carried by said top, an armature for said electrom'agnet, a bearing plate adapted to slide vertically on said supporting stucls'for supporting said armaturein adjusta able relation to the electromagnet, a contact Lfinger mounted on said armature, a fixed contact carried by said top in operative relation to said contact finger, and trunnions for supporting said armature one of which s headless and adapted to be adjusted horizontally during manufacture and the other being provided with a head and removably attached whereby the armature maybe removed from the relay without disturbing the horizontal adjustment. I

18. In combination a relay, a supporting top, an electromagnet and coactingarmature carriedby said top, an articulated contact finger carried by said armature having a main supporting ,member'having a slot formed in the e-ndthereofia secondary contact carrying member pivotally mounted thereon having a contact at the end thereof, a downwardly projecting member at the end of said second ary member having an enlarged end and adapted to project through said slot, and spring pressed'means' associated wit-h the opposite end of said secondary member whereby the contact is free to be depressed upon energization of the relay but is limited in its rela tive vertical movement upon deenergization supporting member having a slot formed in; the end thereof, a vertical stud-having a rounded end carried by said main member, a secondary contact carrying member having an indentation formed therein adapted to coact with the end of said stud to form a pivot and having a contact at the [end thereof, a downwardly projecting meniberat the end of said secondary member having an enlarged.

end and adapted to project through said slot, and spring pressed means associated withthe opposite end of said secondary member,

.whereby the contact-is free to be depressed uponenergization of the relay but is limited in its relative vertical movement upon deener gization of the relay.

20. In combination in a relay, a supporting top, an electromagnet and coacting'armature carried by said top, an articulated contact finger carried by said armature having a main supporting member having a slot formed in the end thereof, a back contact spring rigidly attached to said finger at oneend and free to pass through the slot in the finger at the other end, said end being bent over whereby a definite spring pressure is trapped, a contact on said spring and a coacting back contact carried by said top whereby the trapped pressure of said spring may bereaclily modified to change the pressure on the back contacts when the relay is deenergized,a secondary contact carrying member pivotally mounted thereon having a contact at the end thereof, a downwardly projecting member at the end of said secondary member having an enlargedend and adapted to project through said slot, and spring pressed meansassociated with the opposite end of said secondary member whereby the contactis free to be depressed upon energization of the relay but is limited in its relative verticalmovement upon deenergization of the relay.

21. In COIIlbiDtLlllOIllIl a relay, a supporting top, anelectromagnet and coacting armature carried by said top, an articulatedcontact finger carried by said armature having a main supporting member having a slot forinedin the end thereof, a back contact spring rigidly V 7 attached to said finger at one end andfree to pass through the slot in the finger at the other end said end being bent over whereby a definite spring pressure is trapped, a contact on said spring and a coacting back contact carried by said top, whereby the trapped pressure of said spring may be readily modified to change the pressure on the back contacts when the relay is deenergized, a vertical stud having arounded end carried by said main member, a secondary contact carrying member having an indentation formed therein adapted to coact with the end of said stud to form a pivot and having a contact at the end thereof, a downwardly projecting member at the end of said secondary member having an enlarged end and adapted to project through said slot, and spring pressed means associated with the opposite end of said secondary member whereby the contact is free to be depressed upon energization of the relay but is limited in its relative vertical movement upon deenergization of the relay.

22. In combination in a relay, a supporting top, an electromagnet and coacting armature, carried by said top, a contact finger on said armature comprising a main member and a secondary contact carrying member oscillatably mounted thereon, a spring pressed stud and spring adapted to hold said contact carrying member under trapped tension, coacting contacts carried by said top, and locking ears formed on said contact carrying member, and an enlarged end on said stud adapted to engage said locking ears whereby upon de pression of said spring said stud may be rotated to vary the amount of trapped tension to modify the pressure between the coacting contacts upon energization of the relay.

23. In combination in a relay, a supporting top, an electromagnet and coacting armature, carried by said top, a contact finger on said armature comprising a main member and a secondary contact carrying member oscillatably mounted thereon, a spring pressed stud and spring adapted to hold said contact carrying member under trapped tension, a nut adapted to engage said stud non-rotatably mounted in the contact carrying member, coacting contacts carried by said top and means whereby upon depression of said spring said stud may be rotated to vary the amount of trapped tension to modify the pressure between the coactin g contacts upon energization of the relay.

24:. In combination in a relay, asupporting top, an electromagnet and coacting armature carried by said top, an articulated contact finger carried by said armature having a main supporting member having a slot formed in the end thereof, a nut adapted to engage said stud non-rotatably mounted in the contact carrying member, a secondary contact carrying member pivotally mounted thereon having a contact at the end thereof, a downwardly projecting member at the end of said secondary member having an enlarged end and adapted to project through said slot, and spring pressed means associated with the opposite end of said secondary member whereby the contact is free to be depressed upon en ergization of the relay but is limited in its relative vertical movement upon deenergization of the relay.

25. In combination in a relay, a supporting top, an electromagnet carried by said top, acoacting armature removably supported by said top, a contact finger mounted on said armature, a fixed contact carried by said top in operative relation to said contact finger and trunnions for supporting said armature, one of which trunnions is adjustable horizontally during manufacture, means for fixing said one trunnion in adjusted position, the other said trunnion being removably attached whereby the armature can be removed from the relay without disturbing said horizontal adjustment.

In testimony whereof, I have signed my name to this specification.

OSCAR S. FIELD. 

